Back pain is one of the most significant problems facing the workforce in the United States today, is a leading cause of sickness-related absenteeism, and the main cause of disability for people between the ages of 19 and 45. Back pain can occur from pinching or irritating a spinal nerve, compression of the spine, vertebral shifting relative to the spinal cord axis, and formation of bone spurs. The most common cause of disabling back pain, however, generally stems from trauma to a vertebral disc, such as from mechanical shock, stress, tumors, or degenerative diseases. In many cases, the disc can become permanently damaged or degenerated, such that the preferred treatment necessitates partial or total excision and replacement of the damaged disc.
Traumatic injury to a vertebral disc that is not removed frequently can promote scar tissue formation. Such scar tissue typically is thicker than the healthy tissue, such that the disc continues to progressively degenerate, lose water content, and can stiffen and become significantly less effective as a shock absorber. Eventually, the disc can deform, herniate, or collapse, eliminating the flexibility of the spinal column, and potentially leading to further degeneration or damage to other vertebral discs of the spinal column. At such a point, the only option is for the damaged disc to be partially or completely removed.
When the disc is partially or completely removed, generally it is necessary to replace the excised material to prevent direct contact between the bony surfaces of the adjacent vertebrate on either side of the removed disc. For example, U.S. Pat. No. 6,824,565 of Muhanna discloses a vertebral spacer that is inserted between adjacent vertebrate to provide restorative force and function as a shock absorber between the adjacent vertebrate. Another alternative approach has been to insert a “cage” that can maintain a space occupied by the removed disc to prevent the vertebrate from collapsing and impinging upon the nerve roots of the spine. Still further, spinal fusion has been used to restrict motion and stabilize patients' spines by fusing adjacent vertebrate together. This generally can reduce mechanical back pain by preventing the now immobile vertebrate from impinging on a spinal nerve; however, such stability and pain reduction generally is created at the expense of spinal flexibility and motion. In addition, many conventional techniques for disc repair and replacement can be limited in terms of their size or configuration and thus generally are not designed to accommodate variations in size of the gap resulting from the excising of the vertebral disc material. Further, conventional techniques often cannot accommodate expansion or growth of the spine, frequently requiring replacement of the vertebral spacers with other, different size spacers.
Accordingly, it can be seen that a need exists for a vertebral body replacement and system and method of implanting such a vertebral body replacement that addresses the forgoing related and unrelated problems in the art.